"We have a contract with Wembley, but we have not yet been told that there is a problem or that we won't be able to hold the game there."

An RFU spokeswoman confirmed the Twickenham stadium was available on 26 August, but refused to comment on whether the organisation had been in talks with the RFL.

"There has been a lot of speculation and we don't want to add to that at the moment," said the spokeswoman.

About 35,000 Challenge Cup final tickets have been sold, with many fans travelling to London from rugby league's heartland in the north of England - meaning another venue in the capital is the most likely destination if Wembley is not ready in time.

The BBC has also learned that the delay has also affected four music concerts scheduled for this year.

The building of the stadium has suffered numerous problems, with a roof beam collapsing last week, resulting in building work being cancelled for a day.

There have also been problems with underground sewer pipes at the stadium and workers were sent home on Tuesday after disputes over pay and threats of redundancy.